This invention relates primarily to a tension actuated coupler for a fuel (e.g. gasoline) pump delivery hose which will permit one portion of the hose to be uncoupled upon a tension load of predetermined magnitude being applied to the hose thereby to prevent damage to a fuel delivery pump or station. Alternatively, the tension actuated uncoupler of this invention may be incorporated in the lines supplying the fuel delivery station or pump such that if the pump is run into by a vehicle forceably tearing the pump from its moorings, the supply lines will automatically uncouple and seal. More specifically, this invention relates to such a coupler in which the hose portions, when uncoupled, are sealed so as to prevent the spillage of gasoline or other liquid fuel. Still further, this uncoupler is adjustable so that it may be calibrated (preferably at the factory) to accurately uncouple at predetermined load levels such that the hose is not uncoupled at unduly low loads, but yet which will be reliably uncoupled at predetermined tension loads so as to positively prevent damage to the fuel delivery pump. Also, this uncoupler is so constructed so as to substantially eliminate inadvertent uncoupling of the uncoupler caused by internal liquid pressure.
In recent years, the advent of self service gasoline retail establishments has become a major, if not the predominant, manner in which gasoline and other petroleum fuels are sold at retail. Because customers utilizing self service gasoline pumps are not experienced gasoline service station attendants, and because they do this only occasionally and may be unfamiliar with the gasoline pump, its operation, and the gasoline service station's procedures for dispensing the gasoline and for payment, oftentimes a customer will dispense a quantity of gasoline into his vehicle's tank, pay for the gasoline, re-enter his car and begin to drive away from the service station pump island before he realizes that he has not removed the gasoline pump dispensing nozzle from the filler neck of his fuel tank. In many instances, the nozzle will pull out of the filler neck of the gasoline tank and fall harmlessly to the ground. However, in certain other instances, it is possible to exert exceedingly high tension loads on the fuel delivery hose leading from the delivery pump to the nozzle. More specifically, as an automobile drives off, it is possible to exert such a high force on the delivery hose that either the hose is ripped or torn from the pump, or that the delivery pump is torn free of its moorings to the service station pump island. In either instance, the potential exists for a significant spillage of volatile liquid fuel. Because of the close proximity of electrical power within the gas pump for lighting and the like and because these electrical wires may be ripped from the pump as the pump is pulled from its moorings, electrical sparks oftentimes will ignite any spilled fuel. Of course, with the close proximity of other vehicles and patrons within the service station, the potential exists for personal injury to several such persons in the event such a pump is pulled from its moorings and considerable physical damage may result to the service station such that it would be closed for a considerable length of time for repairs thus representing a significant economic loss to the operators.
In states which require a vapor recovery system for capturing hydrocarbon (e.g., gasoline) vapors as the vehicle is fueled, it would be necessary for the vapor collection system also to prevent damage to the fuel dispensing pump in the event the vehicle drives away from the fueling site with the filling and vapor collection systems attached or inserted in the fuel tank filler neck.
These problems have been recognized in the past. Certain safety code requirements require that the spout for the dispensing nozzle be of breakaway construction such that at moderate loads, the spout will pull clear of the nozzle thus preventing excessive loads from being applied to the pump. However, in actual practice, the fact that pumps are regularly pulled clear of their moorings would indicate that the concept of the breakaway nozzle does not, in all cases, adequately protect against such accidents. Additionally, reference may be made to U.S. Pat. Nos. such as 584,144, 2,048,388, 2,536,702, 3,883,042 and 4,098,438 which are in the same general field as the present invention.
For many years, dispensing pumps in gasoline stations and the like have been prone to being knocked over by vehicles in instances where the vehicle is errantly driven or is involved in an accident. Typically, dispensing pumps are moored to the service station pump island by means of bolts or the like and delivery pipes for the fuel from underground storage tanks are coupled to piping within the dispensing pump. Oftentimes, in the event of a collision, the dispensing pump will be ripped free of its moorings and the supply lines to the pump will be ruptured. Fuel (e.g., gasoline) is typically delivered to the dispensing station or pump from underground storage tanks by a submersible pump. In the event the dispensing pump is ripped free of its moorings and in the event the submersible pump is in operation, it will be appreciated that considerable quantities of volatile fuel may be expelled from the broken supply lines. In an effort to limit the amount of fuel that can be discharged upon a pump being ripped free of its moorings, certain pilot actuated diaphragm valves and other safety devices have been developed which block the flow of fuel upon the pump being ripped from its moorings. One such pilot actuated diaphragm valve is shown in U.S. Pat. No. 4,284,212. However, these various safety means for blocking the flow of fuel from the ruptured supply lines are complex and add considerably to the cost of installing the delivery pump.
Clark, U.S. Pat. No. 2,860,893, recognized this long-standing problem of gasoline dispensing pumps being subject to "pull-away" accidents. Clark disclosed a ball detent coupling which broke away under tension, such as during a pull-away accident.
Recently, an uncoupler of the present invention, substantially identical to FIG. 7 of the previous U.S. patent application Ser. No. 465,242, filed Feb. 9, 1983, and to FIG. 7 herein, was made and sold under license by Emco Wheaton of Conneaut, Ohio. While this uncoupler worked well for its intended purposes, as stated in the above-mentioned U.S. patent application Ser. No. 465,242, it was found, in actual field use, that the uncoupler would, under very low application of tension loads thereto, or even under no tension load condition, inexplicably uncouple. It was found that the dispensers on which these uncouplers were installed are dispensing gasoline at pressure levels far above the pressure levels considered to be maximum desirable operating pressures, as set forth in standards established by Underwriters Laboratory (U.L.). Thus, even in view of such prior art uncouplers as disclosed in Scheiwer U.S. Pat. No. 2,536,702, and Clark U.S. Pat. No. 2,860,893, and in view of the instant inventors' earlier embodiment as disclosed in FIG. 7 herein, a need continued for a tension actuated uncoupler which not only would reliably uncouple at a predetermined tension load applied thereto, but which was substantially unaffected by variations in fluid pressure levels therewithin or by fluid pressure levels considerably above normally expected operating pressure levels.
Further, in fueling vehicles with liquid propane or liquid natural gas fuels, there has been a need for means that would prevent a spillage of fuel in the event the vehicle drove away from the fueling area with the fueling hose still connected to its fuel tank.
In addition, automatic quick coupling kits are available for use on hydraulic systems for farm implements and the like which are connected to a tractor and which are powered by the hydraulic system on the tractor such that if the implement becomes inadvertently uncoupled from the tractor, the hydraulic fittings will automatically and instantaneously break away. Such fittings are commercially available from the Pioneer Quick Coupling Division of Parker Corporation, Minneapolis, Minn. However, these so-called breakaway hydraulic hose couplings require brackets to hold the female coupling and these breakaway couplings have no means for adjusting the force at which the couplings will break away or pull apart. Because of this inability to adjust the breakaway force and because of the wide variety of fuel delivery pumps, a single breakaway tension force would not be acceptable.